The underlying operating system needed to be upgraded into the higher version and customer wanted to check if those application are compatible with the higher version of operating system.
The applications were hardcoded with an IP address, so the target VM should also remain on the same IP address as the source server.
Created a similar network environment with same network CIDR and made that an isolated by restricting any communication to the outside except the 53 for DNS. Created different network with different CIDR for migration which is routable to the source. We have performed the migration successfully and when the migration was completed and we switched the OS to customer source native OS, we pushed that to boot into the isolated network, which prevented the communication of the target VM with the source and avoided the confliction.